The present invention relates to a silencer for exhaust gases from an internal combustion engine of the type having an outer cylindrical cover and a coaxial inner cylindrical tube which define between them an annular cylindrical chamber into which the exhaust gases which enter the silencer are admitted.
The invention also relates to a part of an exhaust line incorporating such a silencer.
The higher temperature of the exhaust gases generally has the disadvantage of causing the constituent materials, and in particular the metals, of the silencers to experience fatigue in a relatively short time such that they are often used beyond the period in which they perform properly.
These high temperatures create total or partial deformation and/or destruction in the exhaust lines, especially in the inlet zone of the silencers, in particular because of a thermal fatigue phenomenon. This phenomenon takes on more and more importance with the widespread use of exhaust lines having catalytic pollution-control units, at the outlet of which the gases commonly reach temperatures greater than 900.degree. C. Furthermore, very high temperatures are not conducive to the use of light alloys, the low density of which would otherwise enable very substantial reductions in weight.
Furthermore, low-frequency vibrations, created by the succession of explosions at certain engine speeds and by the mechanical excitation of certain elements such as the engine-silencer connecting tubes, as well as the transverse partitions of the silencer against which the exhaust gases collide, are a considerable annoyance and cause a dull noise in the passenger compartment of the vehicle.